The present invention relates to the composition of a hybrid reaction resin, particularly a composition of a reaction resin based on a composition that can be cured in a radical fashion and an epoxy resin, as well as its use for the chemical fastening of anchoring means in bore holes.
The use of mixtures of reaction resin based on unsaturated polyester resins, vinyl ester resins, on the one side, and based on epoxy resins, on the other side, as glue and adhesive means has been known for quite some time. This generally relates to two-component systems, with one component comprising the mixture of reaction resins and the other component comprising the curing agent for the resin. Other common components, such as fillers, accelerants, stabilizers, solvents including reactive solvents (reactive diluter) may be included in one and/or the other component. Then, by mixing the two components the reaction is initiated with the forming a cured product.
In particular for the chemical fastening technology, e.g., dowel materials, high requirements are set for the reactive resin materials, because in this application the mechanic strength, the adhesion to mineral underground, as well as to other undergrounds, such as glass, steel, and the like, must be very good. One parameter for the evaluation of the mechanical strength and the adhesive features is the so-called pull-out test. A low pull-out value, also called load value, indicates low tensile strength and little adhesion to the underground. When using reactive resin materials as organic binders for mortar and/or dowel materials high load values must be yielded even under harsh conditions, such as low and high temperatures.
In general, two systems are used in the chemical fastening technology. One is based on ethylene-unsaturated compositions that can be polymerized in a radical fashion, which are generally cured with peroxides, and one is based on epoxide amines. The first system is characterized in a raid curing process, particularly at low temperatures (−10° C.) and is advantageous with regards to load values, particularly at elevated temperatures such as +80° C. for example, however it shows shrinkage, which cannot be ignored. Contrary thereto, the epoxide amine-systems show a slow curing process, particularly at low temperatures (+5° C.) and weaknesses in the load values, particularly at elevated temperatures, such as +80° C., however they develop considerably less shrinkage.
In order to combine the advantages of both systems developments are ongoing in order to develop dual-curing binders. This means, systems with their curing being based both on radical methods as well as on poly-addition. These systems are also called hybrid systems or hybrid binders. These hybrid systems are generally based on resin compositions, which comprise compounds, which can be cured according to the first reaction type, for example compounds that can be radically polymerized, and compounds that can be cured according to a reaction type that is different from the first reaction type, such as compositions polymerizing via poly-addition, for example epoxides. The resin composition based on a compound that can be radically polymerized, and an epoxy that can be cured for example with a peroxide and an amine.
It has not been achieved in prior art to combine the two classic systems to a simple and ready-to-use hybrid system without significantly adjusting and/or altering the classic systems with regards to their formulation, and thus being forced to tolerate the worsening of certain essential features (such as stability at storage conditions, reactivity at high or low temperatures, etc.).
A reaction resin mortar-composition based on a hybrid binder is known from EP 10153243 A1. The hybrid binder is based on a system with a resin component, which comprises a resin that can be radically cured and an epoxy resin, and which includes a curing component, which comprises an aliphatic amine and a peroxide. This reaction resin mortar-composition shows some disadvantages, though.
It is disadvantageous in this reaction resin mortar-composition that the radical polymerization must be activated with the peroxide as the initiator using an accelerator based on a metal salt, in order for the radical polymerization being initiated at room temperature and particularly at low temperatures up to −10° C. According to EP 10153243 A1 this accelerator is included in the resin component, which comprises the radically curable composition.
Another disadvantage of this reaction resin mortar-composition is further that an additional compound is required, which carries two functional groups, with one of them being able to react in a radical (co)polymerizing fashion and the other one to react with an amine, a so-called bridging compound, in order to also improve curing features at low temperature, in addition to the characteristics of the cured material at low temperatures. It has shown that only with this bridging bond satisfactory load values can be yielded at low temperatures.
Further it is disadvantageous that the gel time of the reaction resin mortar-composition can only be extended with stable nitroxyl radicals, because with the common inhibitors, used in addition to the nitroxyl radicals, any extension of the gel time is not possible.
This leads to additional problems, Frequently compounds are added to the resins and/or the resin components which prevent any early radical polymerization, i.e. during storage, in order to provide them with a suitable shelf life. A common and proven compound is 4-hydroxy-2,2,6,6-tetra methyl piperidine-1-oxyl (Tempol), which is used, among other things, to adjust the gel time of a radically curing, unsaturated resin to the desired value. However, it is assumed that in the reaction resin mortar-composition according to EP 10153243 A1 the Tempol, added at least for the adjustment of the gel time, is relatively quickly disintegrated, preventing any lasting extension of the gel time, and a gel time drift is observed. From literature (e.g., Sheldon et al., Org. Biomol. Chem., 2003, 1, 3232; E.G.
Rozantsev et al., Russ. Chem. Rev., 1971, 40 (3), 233) indications are discernible that Tempol reacts with Cu(I) and Cu(II)-salts, which are used, among other things, as catalysts for the activation of the peroxide curing agent, primarily in the presence of the oxygen of the air with OH-functional substances (which are also contained in common mixtures of reaction resins). A quick oxidation reaction is assumed at room temperature. This disintegrating reaction is also assumed for other stable nitroxyl radicals.
The objective of the invention is therefore to provide a reaction resin system, particularly an injection system, for the chemical fastening, which is free from the above-mentioned disadvantages, can be particularly easily yielded from the combination of the reaction resin systems of prior art, and accordingly shows a simple composition, without here the features of the individual reaction resin systems being negatively influenced.